The link between chronic obstructive pulmonary disease (COPD) and functional gastrointestinal disorders (FGIDs) was not well understood. For a study, researchers conducted a countrywide population-based study using National Health Insurance Research Database to investigate the association between COPD and potential FGID development. Between 2000 and 2005, 4,107 COPD patients were included in the COPD cohort. A comparison group of 12,321 age- and gender-matched individuals without COPD was chosen at random. The two cohorts were followed for 5 years to look for the incidence of FGIDs. The results were validated using the operational definition of COPD from the Health Insurance Review and Assessment Service database. The validation research validated the precision of COPD definitions (83.5% sensitivity). 

In patients with COPD, the adjusted hazard ratios (aHR) of FGIDs were greater (aHR: 1.63; 95% confidence interval (CI): 1.45–1.83; P<.001) than in comparison patients. In the secondary study, FGIDs were split into three categories: gastroesophageal reflux disease, irritable bowel syndrome, and functional dyspepsia. Patients with COPD were also more likely to have irritable bowel syndrome (aHR: 1.55; 95% CI: 1.27–1.90; P<.001), gastroesophageal reflux disease (aHR: 2.10; 95%CI: 1.76–2.49; P<.001), and functional dyspepsia (aHR: 1.34; 95% CI: 1.11–1.62; P=.003). The findings in the validated COPD group were consistent with the findings in the unvalidated COPD group. COPD patients looked to be at increased risk for subsequent FGIDs.